The present invention relates to a flyback transformer which supplies a high voltage to a cathode-ray tube of the television receiver, particularly a compact flyback transformer having the terminal pins which can be connected to the printed circuit boards of the television receiver.
As known, a rectified high voltage is supplied to the cathode-ray tube of a television set through the flyback transformer and the rectifier circuit. Some types of conventional television receiver sets are made up by separately fixing the flyback transformer and the rectifier box incorporating the rectifier circuit to the chassis. Since a large space is required, such separate installation is not suitable for relatively small television sets of 10 to 14 inch types.
Therefore, a flyback transformer is developed which has an insulating housing made of a plastic material which houses together the high voltage coil, low voltage coil and rectifying circuits and is filled with an incombustible resin compound to insulate these component from the another.
However, the conventional flyback transformer which houses an insulating housing incorporating the rectifying circuit is made up by assemblying and arranging diodes, resistors, capacitors, etc. with respective support members in a space on the outer periphery of the high voltage coil and filling this space with insulating resin. Therefore, the whole shape of the insulating housing is extended in the radial direction of the high voltage coil and consequently the whole body of the flyback transformer becomes large to be unsuitable for attaching on a printed circuit board with other circuitries because of its excessive occupation of the space. Moreover, it is disadvantageous in that it takes a long time to assemble the parts of the rectifying circuit around the high voltage coil and then set the assembly together with the high voltage coil in the insulating housing.
If the low voltage coil, high voltage coil and parts of the rectifying circuit are not firmly secured at predetermined positions in the housing, a leakage flux and distribution capacity vary with each unit of the flyback transformer to be manufactured and it is difficult to manufacture flyback transformers with stable output characteristics. Furthermore, since the spaces between components (coils, circuitries, housing and bobbin) vary, dielectric strength between these components is not sufficient even though the spaces are filled with insulating resin.